Aero-dynamic wave machine supercharger for steam generators



' Sept. 30, 1958 Filed March 12, 1954 M. BERCHTOLD 2,853,979 AERO-DYNAMIC WAVE MACHINE SUPER-CHARGER FOR STEAM GENERATORS 3 Sheets-Sheet 1 AERO DY VAM WAVE g/IACH/NE INVENTOR. 444x 559017-040 Sept. 30, 1958 M. BERCHTOLD AERO-DYNAMIC WAVE MACHINE SUPER-CHARGER FOR STEAM GENERATORS 3 Sheets-Sheet 2 Filed March 12, 1954 N NE -w MIWH J d p r Sept. 30, 1958 M. BERCHTOLD AERO-DYNAMIC WAVE MACHINE SUPER-CHARGER FOR STEAM GENERATORS 3 Sheets-Sheet 3 Filed March 12. 1954 mu mlm h BY I United States Patent AERO-DYNAMIC WAVE MACHINE SUPER- CHARGER FOR STEAM GENERATORS Max Berchtold, Paoli, Pa., assignor to I-T-E Circuit Breaker Company, Philadelphia, Pa., a corporation of Pennsylvania Application March 12, 1954, Serial No. 415,899

1 Claim. (Cl. 122-4) My invention relates to steam generator systems and is more particularly directed to a novel combination wherein an aero-dynamic wave machine is used as a super-charger for a pressure fired boiler.

Heretofore in the prior art arrangement wherein high pressure air feed to the pressure fire boiler is supplied by an air compressor driven by a gas turbine, several problems are encountered during starting, at low load operation and during transient conditions at increasing load.

My invention also relates to novel control means to insure proper operation during these periods and conditions.

The prior art pressure fired boiler system is generally comprised of the following basic components. An air compressor, a gas turbine to drive the air' compressor, the steam generator or boiler having an evaporator section and a superheater section, a main steam turbine which is fed by the output steam of the steam generator, a condenser and a feed water pump.

This system operates as follows: The feed water pump supplies water to the pipes of the evaporator section of the steam generator. The water is initially heated and steam is generated. The steam is then piped to the superheater section where its temperature is again raised and is subsequently fed to the main steam turbine. The shaft-power of the steam turbine may then be used for any desirable purpose as, for example, to drive an electrical generator, ship propulsion, etc.

After the energy has been extracted from the'st'e'a'm by the steam turbine,- it is passed through the condenser and through the feed water pump back to the evaporator section of the steam generator.

The system for the air which is utilized mixed with the'fuel to heat the water and super-heat the steam is" as follows. An air compressor, which may have an air' feed from the environment of the boiler room, supplies compressed air to the fire box ofthe evaporator section to" aid combustion. The hot gasses are exhausted from the-steam generation and are fed to the gas turbine. After the energy has been extracted from the gas in the rotor of the gas turbine, it is exhausted through a stack; The purpose of the gas turbine is to obtain shaft power to drive the air compressor. Since the hot gas exhaust from the superheater section of the steam generator is required to drive the gas turbine-air compressor combination, it is necessary to provide auxiliary means in order to start the system. That is, auxiliary means must be provided in order to obtain shaft power for the air compressor since there is no hot gas available to" drive thegas turbine when the steam generator system is initially started.

, 2,8533% Patented Sept. se, tees 2 obtained from the output gas thereof, the auxiliary electric'mot'or will then-o erate an electric generator. Also, the auxiliary motor is used when the steam output of the steam generator drops below approximately 20% of maximum capacity.

In order to increase the load, the air flow and fuel feed have to be increased.- However, adding more fuel would not result in an immediate increase in the speed of compressor to get more arc and thus there would be a delay in obtaining increased air flow. During this trans'ient conditiom'the electric motor provides extra power to accelerate the supercharger.

However, this particular arrangement has the disadvantage of requiring an auxiliary piece of equipment, namely, the electric motor.

An alternat'ernethod for obtaining shaft power for the air compressor during starting, low load and transient conditions of the steam generator, is achieved by providing' an auxiliary steam turbine to drive the common shaft of the gas turbine-air compressor combination. The auxiliary steam turbinewill receive energy from steam diverte'd from the mail boiler output through an auxiliary superheater steam outlet, to thereby obtain the required shaft power for the supercharger.

Thus, it will be noted that one disadvantage encountered in this prior art arrangement results from the fact that'shaft power is required in order to drive the air compressor thereby necessitating elaborate auxiliary equipment to be utilized during starting, low load operation and transient conditions.

Another disadvantage of the prior art arrangement is that the gas turbine which provides" the shaft power for the compressor is an expensive and complicated piece of equipment. Furthermore, the system usually requires several stages of high air pressure.

With my novel arrangement, I provide a system which both eliminates the necessity of converting or obtaining shaft power and also eliminates the necessity of utilizing several stages in order to obtain high supercharger pressures. This is achieved by'utilizing an aero-dynamic wave machine as a supercharger for the steam generator system.

Aerodynamic wave machines may be of the type disclosed in my U. S. Patent application Serial No. 454,774, filed September 8,1954 entitled Wave Engine and assigned to the assig'nee of the instant invention. 7 7

Thus, with the useof an aero-dynamic wave machine as a supercharger for the steam generator, the main energy inputto the wave machine is in the form of hot gas which is directly utilized to obtain compressed air. Although means must be provided torotate the shaft of the wave machine, this energy is utilized only to obtain proper timing and does not represent the energy input to the wave" machine. Thus, by utilizing an aero-dynamic' wave machine which requires an energy feed of hot gas and does not-rely on shaft power for its operation, I am able to completely eliminate the necessity of a gas turbine thereby reducing the number of components required. Furthermore, since the compression ratio of the aerodynamic machine can go up to 6 as compared to pressure ratios used in the prior art of 2.5, the necessity of requiring several stages" of compression is completely eliminated and the operating range is substantially extended.

In addition to the above noted advantages, my wave machine can be operated at practically constant speed through the entire load range. That is, since the wave machine operates on the energy of the gas input to the wave machine and not on the shaft power, 'the'rotor speed has only to satisfy the timing requirements. Hence, an auxiliary electric motor canbe provided to drive the shaft of the wave machine at a more or less constant speed;

Although the utilization of an aero-dynamic wave machine as a super-charger for a steam generator or boiler has many advantages over the gas turbine-air compressor combination, the new arrangement nevertheless encounters some similar problems as the gas turbine-air compressor combination during starting, low load operation and transient conditions.

As heretofore noted, compensation for'abno'rmal conditions, namely during starting, low load operation and transient conditions in the prior 'art arrangement is achieved by providing auxiliary equipment such as an electric motor or an auxiliary steam turbine to provide additional shaft power. However, in my novel arrangement, as heretofore noted, no shaft power can be added to the aero-dynamic wave machine so that the problems encountered under abnormal conditions have to be solved by other means.

My novel invention provides means whereby the compressed air flow from the acre-dynamic wave machine to the steam generator can be maintained at a desired magnitude during full load operation of the steam generator and also during starting low load operation and transient conditions. 7

An object of my invention is to provide an aero-dynamic wave machine as a super-charger for the steam boiler whereby means are provided to insure proper operation of the steam system during starting, low load operation and transient conditions.

Another object of my invention is to provide an aerodynamic wave machine as an air compressor for a steam generator whereby a hot bypass of the superheater section can be used to supplement the feed to the wave machine under low load operation and transient conditions.

A still further object of my invention is to provide a novel arrangement whereby a cold bypass for the steam generator and an auxiliary combustion chamber are utilized to supplement the feed to the aero-dynamic wave machine during low load operation and transient conditions of the steam generator.

Still another object of my invention is to provide a novel arrangement whereby an auxiliary blower and an auxiliary combustion chamber can be used as an input to an acre-dynamic wave machine super-charger to insure starting.

Still another object of my invention is to provide a novel arrangement whereby a motor driven auxiliary blower is inserted in series in a cold bypass circuit of the steam generator to thereby provide proper conditions for starting and maintaining proper boiler operation in the entire load range.

A still further object of my invention is the use of an auxiliary blower to increase the flow of compressed air fed to the fire box of the steam generator by direct feed. a

Another object of my invention is to provide a novel arrangement wherein an auxiliary blower provides a direct feed of compressed air to the fire box of a steam generator during starting operations when there is a relatively low airflow output of a wave machine super charger.

A still further object of my invention is to provide a novel arrangement whereby auxiliary means are provided to supply a hot gas feed to an aero-dynamic machine during starting, low load operation and transient conditions.

In the prior art devices difiiculties are encountered during transient load conditions at increasing loads. For example, the following sequence of operation will result when a load of the main electric generator increases. Assuming that the output of the steam generator is at a given level, when the load requirement of the electric generator increases, its R. P. M. will decrease. An automatic control, which is responsive to the R. P. M. of the electric generator, will open up a steam valve to the main steam turbine and hence the steam pressure 4 being fed from the superheater section of the steam generator to the steam turbine will decrease. This decrease in steam pressure will initiate a second automatic operation, to increase fuel flow to the fire box of the evaporator section of the steam generator. However, although the increase in fuel flow will occur instantly, the pressure of steam will not be instantaneously increased since there is no way of instantaneously increasing the pressure of the air being fed to the pressure fired boiler. That is although the temperature of the exhaust gas from the steam generator will be immediately increased when the fuel feed is increased, the increased energy of the fuel must first be connected to the shaft power by gas tubing to thereby result in a substantial delay before there is an increase in the pressure of the air from the compressor.

There the prior art means to rapidly stabilize during transient load conditions utilizes an auxiliary steam turbine to drive a blower with this combination forming an auxiliary super-charger for the steam generator. The combination is automatically rendered effective when it is required to increase the steam pressure, namely, under transient load conditions at increased loads. However, with this arrangement, a portion of the steam which is normally fed to the main steam turbine must be diverted to the auxiliary steam turbine. Thus, this arrangement has the inherent disadvantage of diverting an increased amount of steam from the main steam generator during the period of time when it is necessary to increase the pressure of steam to the steam turbine. Hence, a serious time lag may result before stable operation is achieved.

With the arrangement of my invention a higher steam pressure can be immediately supplied to the steam turbine, immediately following an increase in load on the electric generator.

With my novel system, the fuel flow may be increased on the occurrence of a transient load condition in the same manner as provided in the prior art. However, the reason for the rapid stability during transient conditions is that there is an immediate rise in the temperature of the exhaust gas of the steam generator and since this gas is utilized as a feed to the wave machine, there will be a higher pressure air pressure immediately available to feed the fire box of the steam generator.

The higher pressure air combined with the increased fuel flow to the fire box will thus result in an immediate increase in the pressure of the steam. Thus, without a hot bypass circuit the system would stabilize itself for higher steam pressure with very little time delay since the increased fuel flow would result in higher exhaust gas temperature and thus increase the pressure of the compressed air from the wave machine. This very short time delay can be further reduced by utilizing a bypass circuit so that increased steam pressure is obtained substantially instantaneously.

It will be further noted-that my novel arrangement not only rapidly stabilizes during transient load conditions, but it also eliminates the possibility of an excessively rich fuel-air mixture and the undesirable conditions resulting therefrom. As heretofore noted, in the prior art system resulting therefrom, the pressure of the air does not instantaneously increase during the transient conditions, and hence the increased fuel flow results in a temporary rich fuel to air ratio to create smoke, carbonization and other undesirable conditions.

With my novel arrangement, the pressure of the air to be combined with the fuel is immediately raised by the wave machine thereby eliminating the possibility of an excessively rich fuel to air ratio.

Accordingly, a still further object of my invention is to provide a steam generator system with novel means to rapidly stabilize'the system during rapid load increases.

Another object of my invention is to provide a steam generator system with a wave machine super-charger and by-pass means which increase steam pressure output substantially. instantaneouslyvfollow transientload conditions inin'creasing loads;

Still another object of my invention is to provide'a system in-which the possibility ofan excessively rich fuelairmixture during a transient load condition is eliminated to-thereby avoid the undesirablesmoke and carbonization.

Another. object of my invention is to provide a novel bypasssystem for a supercharger of a steam generator which willnot divert any of the generated steam during transient load conditions.

Still another object of'my invention is to provide a novel steam generator system in which hot gas is diverted from a portion of the steam generator during transient load conditions to thereby enable the system to stabilize itself with no appreciable time lag on the occurrence of a transient load.

These and other objects of my invention will be apparent from the following description When taken in connection with the drawings, in which:

Figure 1 shows a steam generator system in longitudinal section with a wave machine air compressor. This figure represents the first embodiment of my invention wherein a hot bypass is used primarily for low load operation and transient conditions of the steam generator.

Figure 2 is a schematic line diagram illustrating a steam generator installation and illustrates the second embodiment of my invention wherein a cold bypass is provided for the wave machine air compressor which is particularly adaptable for low load operation and transient conditions. The steam system is not shown in Figure 2.

Figure 3 is a schematic line diagram of a steam generator installation of the third embodiment of my invention wherein an auxiliary blower with an auxiliary combustion chamber is provided. This embodiment is particularly adaptable for starting. The steam system of the installation is not shown in this figure.

Figure 4 shows a line diagram of a steam generator installation representing the fourth embodiment of my invention wherein a cold bypass and an auxiliary blower with an auxiliary combustion chamber is provided for the. wave machine to aid during bothstarting low load operation and transient conditions.

Figure 5 is a schematic line diagram ofa steam generator installation illustrating the fifth embodiment of my invention wherein an auxiliary blower is used in conjunction with a hot bypass to aid during both starting, low load operation and transient conditions.

Figure 6 illustrates a steam generator installation illustrating the sixth embodimentof my invention in which an auxiliary blower is used in'conjunction with a cold bypass in order to aid in both starting, low load operation and transient conditions. Figure 6 also illustrates an adaptation which may be utilized in connection with my invention whereby a second wave machine may be utilized either as a substitution fora first wave machine or to supplem'ent same during certain'predetermined operations and conditions;

Referring now to Figurehthere is shown a steam generator 200 which is comprised of the evaporator section 20 1 and the superheater section 202. A water feed pump 203 is provided to supply water to the evaporator section 201 of the steam generator 202. The water is fed into the steam generator 202 by means of the piping system 204. A fuel valve 102 controls the fuel flow into the fire box section 100 of the evaporator 201. Thi fuel is sprayed into the compressed air which is fed into the fire box 101 by means of the pipe system 101. The compressed air and fuel is ignited in the fire box 100 to thereby raise the temperature of the water fed through the piping system 101 and change this water to steam.

The water in the pipes 209 is raised above the boiling point, it is passed through the pipe 210 to the superheater. section 202 of the steam generator 200. The hot gas from the fire box 100 of-the evaporator section 201 6 is alsoapassed tothe superheater section 202.through the duct-211;

The steam is superheated in the superheater section 202 and is then provided asan input to the steam turbine 212. The shaft power output of the steam turbine 212 may then be utilized 'inan'y desirable manner as for'example to drive the electric generator 213.

After the energy has been extracted from the superheated steam by the steamturbine 212, thesteam is passed through the condenser-214,and thence, back through the water feed pump 203 to repeat the cycle just described.

As heretofore noted, the compressed air is fed into the fire box section 1000f the'evaporator 201 bymeans of the piping system 101. Thecompressedair system will now be described.

An aero-dynamic wave machine 10 isprovided with its output D to supply compressed air to the piping system 101. The compressedairoutput of the wave machine 10'is fed into the fire .box.100 where fuel isadded from the fuel valve 102.

Following combustiontinthe'fire. box 100, the heated gas is passed throughathe'duct work 211 to the superheater section202 of thesteamgenerator 200 to furtherraise the temperature ofthe. steam. The gas :from the superheater section 202 is then piped through the piping system 103 to an input C of the wave machine 10.

The instationary flow operation of the aerodynamic wave machine 10 is disclosed in. my heretofore referred to copending application.

A brief descritpion of themechanical components of the wave machine 10 is as follows:

A prime mover 11 drives the rotor 12 through the shaft.13. The rotor 12 .is provided with a plurality of cells or channels 14 which rotate past the input and outputports A, C and,fB, The port D is an output for the wave machine to.-supply compressed air to'the steam generator through the piping system 101. The port C is provided as an input to the wave machine 10 so that the energy of the exhaust gas from the superheater section 202 can be fedthrough pipe 103 into the wave machine.

An input port A is provided so that the blower 15 can scavenge theycells or channels 14 with fresh'air as described inmy two above applications. Port B is providedwithexhaust. gas from the-wave machine 10. The prime mover 11, which may be an electrical motor or a steam turbine, is provided only for the purpose of proper timing for the expansion and compression Waves to insure'that maximum eificien-cy, as described in the above mentioned .copending applications.

The primary energy feed to .thewave machine 141 is not derived-from the prime mover 11 but rather from the energyof the hot gas'which is exhausted from'the superheater section 202 and fed to the'wave machine 10 through the port C. By utilizing anaero-dynamic wave machine as a supercharger for the steam generator, the vmain energyinput to the. wave machine is derived from the expandinggas which is the exhaust from the superheater section 202. The means provided to rotate the shaft 13 of the wave machine 10 is utilized only to obtain the proper timing of the ports A, B, C and D with respect to the channels 14.

As noted in the introduction of the specification, the prior art arrangement utilizes shaft power to operate an air compressor and thus must convert the energy of the steam generator exhaust gas into shaft power to drive an air compressor.

Since the aero-dynamic wave machine 10 only requires the energy of the exhaust hot gas of the superheater section 202 and does not require shaft power other than that needed for timing operations eliminates the necessity for a gas turbine and therefore reduces the number of components required for the super charged steam boiler installation. Furthermore, since the compression ratio of the acre-dynamic wave machine 10 is 7 in the vicinity of 6 as compared to the prior art arrangement of approximately 2.5, the necessity of requiring several stagesof compression is completely eliminated and the size and weight of the actual boiler is greatly reduced.

Since the wave machine 10 utilizes the energy from the superheater section 202, it is necessary to provide additional means in order to aid the system during starting low load operation and transient conditions.

In Figure 1, I have shown the first embodiment of my invention wherein a hot gas bypass 105 of the superheater section 202 is provided. This system is particularly adaptable for low load operation. Thus, for example, when the load requirements of the steam turbine 212 drop below of the maximum load, the combustion temperature of the gas will decrease thereby resulting in a decrease of the temperature of the exhaust gas from the superheater section 202. This decrease in the temperature of the feed gas to the Wave machine 10 may result in unstable operation. If the temperature of the exhaust gas falls below the required temperature of the wave machine, operation is no longer possible, hence it is necessary to raise the gas temperature.

By utilizing a hot bypass 105, it is possible to maintain the required energy level for wave machine 10 for the range from 20% to 100% load of the steam generator, the valve 106 in the hot bypass 107 is closed so that no .gas is diverted from the superheater section 202. However, below 20% load, the valve 106 is automatically opened. The control system for rendering the valve 106 responsive to low load operation or transient conditions may be of any desirable pick-up system well known in the art. Thus, when the low load operation or transient conditions occur, the valve 106 will be opened to thereby divert the gas from the superheater section 202 through the hot bypass 105 to provide the necessary gas temperature for the wave machine 10.

It will be noted that in this embodiment, there is a continuous feed to the wave machine 10 from the superheater section 202, supplemented by the hot gas which flows through the hot bypass 105 during predetermined operating conditions.

As fully explained in the introduction of this specification, the various embodiments of my invention not only aid during starting and low load operation but will also result in rapid compensation during transient load conditions during increasing loads. That is, there will be an immediate increase of steam pressure to the steam turbine 212 on the rapid increase to the load of the electric generator 213. The reason for the rapid stability for the transient condition is as follows:

The fuel feed valve 102 may be rendered responsive to the pressure of the steam in any manner well-known in the art. Hence, when the load suddenly increases and the pressure of the steam decreases the fuel flow through valve 102 will be immediately increased. This increase in fuel flow will result in a greater combustion and hence will raise the temperature of the gas. Since this gas is utilized in the wave machine, a higher air pressure will instantly be available to the fire box 100. The combined increased fuel flow and increased pressure of the air in the fire box 100 will result in an increase of the steam pressure with very little delay time. This period can be further reduced by making the valve 106 responsive to steam pressure so that on these will be an immediate increase in the feed gas to the wave machine 10 through the hot bypass 105. With this arrangement, the system can be stabilized with substantially no delay. The increase in pressure of the steam. will then result in the automatic closing of the valve 106. Since this is utilized in the wave machine, a higher air pressure will be instantaneously available in the fire box 100 of the steam generator 200.

In addition to rapid compensation for transient load conditions, the system described in connection with my invention'will also eliminate the necessity for an unduly rich fuel-air mixture and undesirable conditions, such as smoke and carbonization, resulting therefrom on the occurrence of a transient load condition.

The second embodiment of my invention is illustrated in Figure 2. This figure is a schematic representation of the longitudinal section of the steam generator installation shown in Figure 1. The steam system comprising the components of the water pump 203, piping 204 and V 209, steam turbine 212, condenser 124, and generator 213 are eliminated in Figures 2, 3 and 4 for the sake of simplicity.

In the second embodiment of my invention, I have shown a cold bypass with an auxiliary combustion chamber 20 which is utilized primarily to compensate for low load operation and transient conditions. The cold bypass system is comprised of an auxiliary combustion chamber 20 which is inserted between the air feed pipe line 101 of the fire box and the gas exhaust pipe line 103 of the superheater section 202. Valve unit 21 is inserted in series with the auxiliary combustion chamber 20. The valve 21 is automatically closed during operation between 70% and 100% load of the steam generating system and, hence, there is no flow through the auxiliary combustion chamber 20. However, the valve 21 is automatically opened during low load operation. The valve 21 may be responsive to these conditions in any manner which is well known in the art. Thus, for example, during low load operation when the temperature of the exhaust gas from the superheater section 202 decreases, the valve 21 will open up to thereby divert a portion of the compressed air output of the wave machine 10 through the piping system comprising the cold bypass of valve 21 and auxiliary combustion chamber 20;

The auxiliary combustion chamber 20 will raise the temperature of the compressed air diverted through the cold bypass so that its energy level will be substantially equal to the energy level of the exhaust gas in the superheater section 202 when the steam generator installation is operating under full load.

Since the valve 21 can be made responsive to the magnitude of the load, it will be possible to divert a decreasing amount of compressed air from the line 101 as the load increases, and after the load reaches a predetermined percentage, for example 30% of full load, the valve 21 will be completely closed so that the compressed air is no longer diverted from the feed line 100.

The third embodiment of my invention is illustrated in Figure 3 wherein an auxiliary blower 30 and an auxiliary combustion chamber 31 are provided to supply a hot gas feed to the wave machine 10.

As heretofore noted in connection with the embodiments illustrated in Figures 1 and 2, the hot bypass and cold bypass are particularly adaptable for low load operation and transient conditions. However, it is desirable to provide means which will also provide gas of proper energy to the wave machine 10 during the starting operation of the steam generator installation.

In the third embodiment, a prime mover, for example an electric motor 32, is provided to drive the blower 30 which provides compressed air to the auxiliary combustion chamber 31. The hot gas of the auxiliary combustion chamber 31 is fed through the valve 33 and through port C to the wave machine 10.

In the third embodiment, shown in Figure 3, as well as in the embodiments four, five and six, shown in Figures 4, 5 and 6, respectively, the auxiliary means secure starting, low load and transient operation, thereby overcoming any disadvantages which may be encountered in the embodiments of Figures 1 and 2. Thus, for example, in the embodiment of Figure 3, the valve 33 is re sponsive to low load operation and will be in an open position when it is desired to start the steam generator. Automatic means for opening the valve 33 during start- 9 ing, low load operation and transient conditions may be of any, desirable system wellv known in the art.

It will also be noted that [any means wellknown in the art can be provided to render the prime mover operative whenever the valve 33 is open. Thus, during the starting operation whenthere isno hot gas exhaust available from the superheater section 202 to the piping 103, the auxiliary means 31, 32,33 will furnish .compressed hot gas to the wave machine 10. That is, the motor 32 will drive the auxiliary blower'30 to provide a feed to the auxiliary combustion chamber 31.

The heated gas from the, auxiliary combustion chamber 31 will be fed through the valve 33 to the port C of the wave machine 10. Thus, although there is no hot. exhaust emanating from the superheater section 202 of the steam generator 200 during starting, the auxiliary means 30, 31, 32, and 33 will provide the hot gas to the wave machine 10.

In addition to providing hot compressed gas to the wavemachine 10 during starting operation, the auxiliary system 30, 31, 32, 33 will be rendered operative during low load operations to insure continuous flow of hot gasses into the wave machines during this period of time.

When the steam generator is operating above 20% load, the valve 33 will be closed and the prime mover 32 will be rendered inoperative when sufiicient energy can be obtained from the exhaust gas of the superheater 202.

The fourth embodiment of my invention is illustrated in Figure 4 and utilizes the cold bypass principle described in embodiment two as well as an auxiliary blower inserted in series therewith. This arrangement is adaptable to compensate for both starting, low load operation and transient condition.

The basic components for the embodiment of Figure 4 are comprised of the auxiliary combustion chamber 40, the blower 41 and the valve 43 which comprise a cold bypass for the steam generator 200.

During starting operations, the motor 42 is rendered operative to drive the auxiliary blower 31 to thereby provide compressed air to the auxiliary combustion chamber 40. The hot gas ofv the auxiliary combustion chamber 40 is utilizedto .compressair in the wave machine 10, even though there is no exhaust gas in the line 103 from the superheater section 202.

By providing compressed hot gas to the wave machine 10, it is possible to obtain a compressed air output therefrom through the port D. After the steam generator 200 has started and there is sutficient energy available in the exhaust gas from the superheater section 200, the motor 42 will be rendered inoperative in any desired manner. That is, control circuit for the motor 42 can be provided so that it will not drive the blower 41 when the steam generator 200 is operating. The motor 42 can also be made responsive to transient load conditions during in- .creasing loads to thereby increase the air flow through the combustion chamber 40.

During starting operations, the valve 43 may be closed so that the entire compressed air output of the wave machine is fed into the fire box 100 of the evaporator section 201 and the combination 4142 will supply sufiicient hot gas to stabilize the wave machine 10. However, under low load operation, a portion of the output of the wave machine 10 will be diverted through the cold bypass into the combustion chamber 400 to thereby maintain a proper energy supply to the wave machine 10. The operation of this system is substantially the same as heretofore described in connection with the embodiment of Figure 2.

During the low load operation, it may not be necessary to utilize the motor 42 and, hence, it can be made responsive to load conditions so that it is rendered inoperative following a starting operation.

In the fifth embodiment of my invention, shown in Figure 5, I have combined the principles of the hot bypass shown in embodiment one with a motor driven blower furnishing compressed air directly to the fire box 100.

sesame The hot by pass105 and the controlling valve 106 will operate in substantially the same manner as heretofore described in connection with hot bypass 105 of Figure 1. However, in addition to'this unit, an auxiliary blower 50 with a primemover 51 and a valve 52 is provided to feed compressed air to the fire box of the evaporator section 201 of the steam generator.

The hot bypass is primarily adaptable for low load operation-and transient conditions. Although the valve 52 can be made-responsive to load magnitude and change, the auxiliary components 50, 51 and 52 are utilized primarily for starting operations. Thus, for example, when thesteam. generator installation is to be started and there 'is no compressed hot gas available to the wave machine 10, there will be no source of compressed air for the fire box 100. However, by providing an auxiliary blower 50 driven by the prime mover 51 which can be rendered operative in any desirable manner known in the prior art during starting conditions, a source of compressed .air will be available for the fire box 100. That is, the valve 52-will be open and the prime mover 51 operative during the starting operations so-that the. blower 50 will provide compressed air feedto the firebox 100-of the evaporator section 201.

Following starting operation, the valve 52 can be closed and the prime mover 51 rendered inoperative. 1 When the steam generator is operating under full load, the valve 106 will.v be closed, thereby rendering the hot bypass ineffective. Thus, the embodiment of Figure 5 may be utilized for starting, low load operation and transient conditionsto insure that there is enough hot gas available to the wave machine during all conditions to maintain the proper pressure of the. air to the fire box 100 of the steam generator 200.

The. sixth. embodiment of my invention is illustrated in' Figure 6-wherein a cold bypass of the type illustrated in the -.er'nbodiment of Figure 2 is utilized in connection with a motor driven auxiliary blower 50 of the type shown .in the embodiment of Figure 5. Thus, in the sixth embodimentof my invention, it is also possible to provide for both starting, low load operation and transient conditions.

The cold bypass circuit 20-21 operates in the manner heretofore described in connection with Figure 2. The auxiliary blower system 50.51'53 operates in the manner heretofore described in connection with Figure 5. Thus, during low load operation, the valve 21 will be open to thereby divert some of the compressed air from the fire box 100 through the cold bypass to the auxiliary combustion chamber 2!. However, when the steam generator system has reached a predetermined percentage of full load, for example above 20%, the valve 21 will be automatically closed in any manner well known in the art so that the compressed air will no longer be diverted from the fire box 100.

When the steam generator is to be started, the valve 52 is opened and the prime mover 51 is rendered operative so that the motor driven auxiliary blower 50 will serve as a source of compressed air to the fire box 100.

Accordingly, I have provided a novel steam generator installation wherein an acre-dynamic wave machine is utilized as an air compressor and in which means are provided to insure proper operating conditions of the installation during starting, low load operation and transient conditions.

Furthermore, since my novel arrangement utilizes the energy of the exhaust gas of the steam generator to drive the Wave machine and does not rely on shaft power, there is an immediate response to transient load conditions at increased loads so that the system can be stabilized without any substantial time delay.

Furthermore, since the system has rapid response, thereby resulting in increase in the pressure in the output gasses of the wave machine on the occurrence of a transient condition, the possibility of an unduly rich fuel air mixture is eliminated.

In Figure 6, I have shown an adaption which may be utilized in connection with my invention whereby a standby wave machine can be connected into the steam generator installation as a substitution for the main wave machine 10 or to supplement the output of the main wave machine 10.

In some applications of steam generators, it may be desirable to provide an arrangement wherein a damaged unit can be immediately substituted by a second unit.

With the embodiment shown in Figure 6, the main wave machine 10 and the standby wave machine 10' are connected in parallel to the compressed air feed line 110 and the gas exhaust line 103. The main wave machine 10 is connected to these lines by means of the valves 70 and 71 and the standby wave machine 10' is connected thereto by means of the valves 7071. In the event the main wave machine 10 is damaged, the valves 7071 can be closed and the valves 70'7 1' can be opened thereby substituting the standby wave machine 10' for the main wave machine 10.

In some installations wherein the steam generator operates under a relatively low load during a portion of the day and a relatively high load for another portion of the day, it may be desirable to have different Wave machines for these two conditions. That is, when the load requirements of the steam generator are low, the compressed air .need only be of a relatively low mass flow and a low pressure whereas when the load increases, the compressed air will have to be of a relatively higher mass flow and higher pressure.

Thus, for example, assuming that the wave machine 10 has a relatively low mass flow and low pressure output at optimum operating conditions and the wave machine 10' has a relatively high mass flow and high pressure output at optimum operating conditions, the valves 7071 would be opened and the valves 70'-71' would be closed when the load of the steam generator installation is low. However, when the load requirements of the installation are increased, the valves 70'71' can be opened to provide a larger quantity of compressed air to the system. In the event that the wave machine 10' by itself supplies a suflicient quantity of compressed air, then the valves 7071 can be closed at this time.

In the foregoing, I have described my invention only in connection with preferred embodiments thereof. Many variations and modifications of the principles of my invention within the scope of the description herein are obvious. Accordingly, I prefer to be bound not by the specific disclosure herein but only by the appending claim.

I claim:

A steam generating installation comprising a steam generator and an aero-dynamic wave machine; said steam generator having an evaporator section and a superheater section; a fire box in said evaporator section of said steam generator; a fuel feed to said fire box; a first pipe connecting an output of said aero-dynamic machine to an input of said fire box; said aero-dynamic wave machine supplying compressed air through said first pipe to said fire box of said evaporator section; combustion of said fuel and said compressed air in said fire box providing hot gas; said hot gas converting water in said evaporator section to steam; said steam generated in said evaporator section being fed to said superheater section of said steam generator; said hot gas fed from said evaporator section to said superheater section; said hot gas in said superheater section superheating the steam therein; a second pipe connecting an output of said superheater section of said steam generator to an input of said aerr dynamic wave machine; said hot gas being exhausted from said superheater section of said'steam generatorthrough said second pipe to said aer'o-dynamic wave machine; the energy of said hot gas to said acre-dynamic wave machine being converted to said compressed air within said aerodynamic wave machine without conversion to shaft power; means to divert a portion of the hot gas flow from said evaporator section to said superheater section so said aero-dynamic wave machine on the occurrence of a predetermined load condition; means including an auxiliary blower to feed compressed air to said fire box of said evaporator section from said auxaliary blower when said steam generator is being started.

References Cited in the file of this patent UNITED STATES PATENTS 1,993,746 Noack Mar. 12, 1935 2,399,394 Seippel Apr. 30, 1946 2,526,618 Darrieus Oct. 24, 1950 FOREIGN PATENTS 407,158 Great Britain Mar. 15, 1934 

